Why is my Thrunite TN-30 flickering on high/turbo?

I just got the light on Saturday, and I have not really had a chance yet to go out into the country and crank it up and see how good it throws and how bright it is in the open. But I have turned it on the highest setting(2700L) for very short periods like less than 30 seconds. But it wasnt until last night that I noticed the flickering.

I was doing a ceiling bounce test to see how well it lit up the room around me, and I had done this before, but I always looked around the room at the light it was producing, but I didnt look closely at the beam on the ceiling til last night. When I did, I noticed that it flickers about once or twice every second or two. Its not a regularly timed flickering, its somewhat random in timing. It doesnt flicker all the way down to off/no light, but when it flickers it gets a bit dimmer, and each flicker only lasts a fraction of a second. Its pretty obvious though.

But when I switch down to the next lowest setting(1500L), or any lower setting, the flickering stops abruptly. I am using Orbtronics 2900mah protected Panasonic 18650's. All 3 were bought about 2 months ago, 2 weeks apart, and 2 were spares that only went through 2 partial recharge cycles(charge discharge and recharge), and the 3rd one was used in a single 18650 light, and was cycled for partial charge 3 times. So they certainly are not old, well used batteries!

What could be causing this phenomenon, has anyone else seen this with this light or with other high lumen lights? Is it a big deal, and what to do about it? Its only happening at the highest setting.

Thanks...

You made me curious. I have a TN31 and just did the ceiling bounce. No flicker. The TN30 share many parts with the TN31. I would clean all threads & contacts. Then charge the cells and check the voltage fresh from the charger. Make sure everything is tight. If it still flickers I'd email the vendor who sold it to you and request an RMA. New Thrunite flashlights don't flicker. They should repair or replace it for you.

HotWire said:

You made me curious. I have a TN31 and just did the ceiling bounce. No flicker. The TN30 share many parts with the TN31. I would clean all threads & contacts. Then charge the cells and check the voltage fresh from the charger. Make sure everything is tight. If it still flickers I'd email the vendor who sold it to you and request an RMA. New Thrunite flashlights don't flicker. They should repair or replace it for you.

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Aside from the outward appearance of the TN30 and TN31 being similar, the 2 lights are very different. The TN31 has 1 XM-L and is a thrower that runs at 1150L, whereas the TN30 has 3 XM-L, is somewhat more floody and runs up to 2700+ lumens. I was thinking that maybe the high current demand to run the light at 2700+ lumens was causing the flickering somehow.

Well, before it kept flickering each time I tried it out on the ceiling, but then I decided to finally take a drive over into rural Md and Pa, and try it out in a few dark fields. Unfortunately, we are having yet another super humid night with thick humidity and what even looks like mist hanging in the air, so that severely limited my testing because all that moisture seems to absorb a significant amount of light, or reflect it. But I would stop here and there, shut my headlights off, get out and shine it across a field here and there, and then I came home and did the ceiling bounce test again just now, and it doesnt seem to be flickering now.

I had fully charged these batteries before I installed them into the light, because I wanted to make sure they all had an equal charge. So I'll have to keep trying it out and see if the flickering is over and done.

I read in a few reviews of these lights that it was difficult to get the battery holder into the body because it is such a tight fit when all 3 18650's are installed, but with the Panasonic Orbtronics cells I used, there was absolutely no difficulty getting the battery holder into the body. It just dropped right in with no resistance! Did you have any difficulty?

HighlanderNorth said:

I read in a few reviews of these lights that it was difficult to get the battery holder into the body because it is such a tight fit when all 3 18650's are installed, but with the Panasonic Orbtronics cells I used, there was absolutely no difficulty getting the battery holder into the body. It just dropped right in with no resistance! Did you have any difficulty?

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I have the TN31 and am using EagleTac 3100's and I have no problem getting the tube into the body. Hopefully this is the end of your problems. You have not had the best of luck with your new lights recently.

biglights said:

I have the TN31 and am using EagleTac 3100's and I have no problem getting the tube into the body. Hopefully this is the end of your problems. You have not had the best of luck with your new lights recently.

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Yeah, tell me about it! I sent the TK41 back and replaced it with this light, so I hope this little issue is finished. I am thinking about buying another TK41 though, but I want to wait til I can get the newer 860L U2 model. I really liked that light, but the on/off switch was screwy, so.........

I read another thread with similar problems, and it was the batteries.

Thrunite also does a feeble job of screwing the led and circuit assembly into the heads

you should disassemble the head and then screw the pill in -really tight-

The usual problem with flickering in 3 x XM-L is usually the batteries or a lose connection. When using high output lights it is always better to usr good quality 18650 cells.

I have had my TN31 for several weeks now and I have not encountered any flickering.

Now mind you, I have in other lights from time to time and it has always been a simple case of wiping the ends of the body tube where it seats up against the inside of the tailcap. Small traces of lube will find its way onto that surface and this will cause it. Even with light lubing, when checking or changing batteries there will always be some degree of migration of some lube. A quick wipe and all is well again.

And by the way....I just love this TN31. Enjoy yours!

For the record, Eagletac 3100 18650's are lighting up mine.

loquutis79 said:

I have had my TN31 for several weeks now and I have not encountered any flickering.

Now mind you, I have in other lights from time to time and it has always been a simple case of wiping the ends of the body tube where it seats up against the inside of the tailcap. Small traces of lube will find its way onto that surface and this will cause it. Even with light lubing, when checking or changing batteries there will always be some degree of migration of some lube. A quick wipe and all is well again.

And by the way....I just love this TN31. Enjoy yours!

For the record, Eagletac 3100 18650's are lighting up mine.

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I am debating getting a TN31 as a dedicated thrower, as I dont have a dedicated hard core thrower. I have lights that throw pretty well for their size, but none of them are really dedicated throwers, as they are designed as EDC lights that run on 1-CR123 or 1-18650. The reason I bought the TN-30 was that I needed a really bright light to take the place of a 12v, auto cigarette lighter powered spot light that you can light up large areas with, and the TN-30 seems to be pretty good at that, although the one time I've now tested it for that purpose, it was last night, and it was really humid outside with mist in the air, so it wasnt the best situation.

But after I took it out last night and shined it on a few fields to see how well it lights up a large area, I came back home and did another ceiling bounce test, and the flickering seemed to have stopped. I just tried it again for the 1st time tonight, and it flickered for about 2 seconds when I first turned it on turbo, but then abruptly stopped.

I dont think its a big problem. I also took the time to clean the threads and remove some machining dust/debris and add a little new lube, so maybe that helped. That and the batteries have now undoubtedly dropped from 100% charge to probably 80%, so maybe that somehow has something to do with it, and that probably doesnt make sense, but who knows........




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HighlanderNorth said:

I am debating getting a TN31 as a dedicated thrower, as I dont have a dedicated hard core thrower. I have lights that throw pretty well for their size, but none of them are really dedicated throwers, as they are designed as EDC lights that run on 1-CR123 or 1-18650. .

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I am pretty sure that u would enjoy the TN31. With the lower levels it can take the place of other lights, very handy. It throws farther than my TK70, at a fraction of the size!

The Thrunite TN31 is certainly worth a purchase. The throw is amazing and it certainly has the wow factor about it. The control ring is a nice touch too.